The Mini Balloon Kit is based around the 36 inch wide mylar foil balloons found by contributor @patcoyle -- which are much cheaper (as little as $3 each!), and can stay inflated for over a week. They fit in the back seat of your car, or can be taken on the subway. Heck, unlike the big red rubber balloons, they fit through a doorway.

Materials

• 2-3 36 inch mylar balloon
• 1000 feet of 50-pound kite string
• carabiners, zip-ties, other clips and such to attach it all together
• a camera that weighs less than 60 grams

Each can lift about 50 grams -- vs. the classic kit’s 300+, and a little more if there’s perfectly calm weather. Instead of renting a helium tank, you can fill them at a florists’ shop or party store, and shuttle them to where you’ll do your mapping. They also hold up a bit better to sunlight and rough handling, although they’re still delicate. This kit includes everything from the classic Balloon Mapping Kit, but uses smaller mylar balloons, and uses lighter (50 lb test) weight string.

We’ve collected a list range of cameras -- like the Mobius camera we already sell -- light enough to work with 2-3 of these. With a lighter option, that means you'll have a spare balloon.

But there are remaining questions and refinements to make on this kit -- that’s why we’re calling it a Prototyping Kit -- and, just like the original Balloon Mapping Kit, we’re going to collaboratively work on these issues by sharing knowledge on the Public Lab website.